Glazed pads and/or bad vacuum booster are a red herring. You're not getting sufficient clamping which would lead me to think that the master isn't providing hydraulic pressure or something is preventing the caliper piston travel. Since ( or if) the car is not pulling to one side or the other I'm putting my money on the master. I would also recommend replacing the flex lines. They rot from the inside and could look just fine but be almost completely blocked...